Sound Quality and Compression

**Shizam76** · 07-24-2012, 06:22 PM

Hey everyone. I am back from the darker side (was with at&t...left for sprint....now back to at&t 2.5 years later).

I have noticed that the sound quality of calls is different than sprint. A crappy codec....compressed voice...not sure what the reasoning is. I'm not the only one to notice. Certain words sound kind of blended or overmodulated...I guess that is the compression. Sometimes if you are doing something in the background it is hard to understand all words coming from the person you are talking to. It's better using the handset, but I use the blue ant bluetooth headset most times.

A few years ago when I had at&t before, talking on my bluetooth, ANY background noise was so loud and overbearing for my caller that they would have to move the phone away from their ear. Just like today, I moved a pot into the sink and it made a clank sound. My caller stated it sounded like I just broke a stack of dishes. He stated that it was not like that when I used to talk to him when I had sprint.

People now tell me to turn my headset down because they can hear themselves speaking back.....bad...along with some feedback (that I don't hear). So, I turn the headset down 3-4 clicks and they say this is better. However now I almost have to hold still to hear everyword. If I am driving with that driving hum in the background....or the dryer is going at home in the background, half the conversation is too quiet. If I turn the headset up to hear better, then my caller starts hearing themselves again (audio is circulating from the piece in my ear to the microphone). On sprint, I had my headset up on full blast most times and it was never a problem.

The one friend I talk to who is in the PC tech field said the above things are the way they are because of the codecs and compression at&t uses...they are different from sprint and are much lower quality.

Anyone out there with any knowledge of the audio....and maybe know when this could possibly improve?

Other then that...its good to be back! And have a signal! And have a decent data connection.

**zephxiii** · 07-24-2012, 06:51 PM

What phone are u using? Sound quality is greatly affected by the device and if u r using Bluetooth then that is another call quality problem in itself.

In the iPhone call quality comparison Sprint was rated the highest, ATT second, vzw last....and I think sprint only won in outgoing quality, and was second to ATT in incoming.

Generally for me ATT has been great on 3G....just made a call to my sister today who is on a Q9h with crystal talk and she sounded awesome on it!

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**Shizam76** · 07-24-2012, 07:19 PM

Originally Posted by zephxiii

What phone are u using? Sound quality is greatly affected by the device and if u r using Bluetooth then that is another call quality problem in itself.

In the iPhone call quality comparison Sprint was rated the highest, ATT second, vzw last....and I think sprint only won in outgoing quality, and was second to ATT in incoming.

Generally for me ATT has been great on 3G....just made a call to my sister today who is on a Q9h with crystal talk and she sounded awesome on it!

Sent from my Nexus One using HowardForums

I'm using the galaxy s III. Its just weird I remember these same exact things happening 2.5 yrs ago on my treo 750....and cheapie bluetooth.

**spdickey** · 07-24-2012, 07:38 PM

Originally Posted by Shizam76

I'm using the galaxy s III. Its just weird I remember these same exact things happening 2.5 yrs ago on my treo 750....and cheapie bluetooth.

Codecs also vary depending on the tower you are connected to. Take a gander at this discussion about 4G and 3G codecs when LTE was being launched.

http://3g4g.blogspot.com/2010/02/codecs-for-lte.html

**formercanuck** · 07-24-2012, 08:02 PM

I have both an iPhone 3GS and a Samsung SII. The Samsung SII typically sounds a bit muffled in comparison (using the same iPhone corded headset, calling the same landline).

I've found over the years that Sprint has typically a VERY clean sound, but at the same time - due to the codec, you will not pick up anything that is soft (ie. background noise is always chopped to save bits at an extreme rate). Many times, I thought that the other side had disconnected or my call dropped.

EFR and AMR-Full rate codecs are VERY good, and effectively land line quality - without cutting background noise. I suspect that most (all) networks are set to AMR-half rate or anything even 'more' efficient (poorer quality). Skype actually has better audio at times.

**jonbruce** · 07-26-2012, 09:15 AM

How can you tell what codec you are using on the iPhone? Will the *3001#12345# mode tell me this?

Originally Posted by spdickey

Codecs also vary depending on the tower you are connected to. Take a gander at this discussion about 4G and 3G codecs when LTE was being launched.

http://3g4g.blogspot.com/2010/02/codecs-for-lte.html

**Shizam76** · 07-26-2012, 12:11 PM

Originally Posted by formercanuck

I have both an iPhone 3GS and a Samsung SII. The Samsung SII typically sounds a bit muffled in comparison (using the same iPhone corded headset, calling the same landline).

I've found over the years that Sprint has typically a VERY clean sound, but at the same time - due to the codec, you will not pick up anything that is soft (ie. background noise is always chopped to save bits at an extreme rate). Many times, I thought that the other side had disconnected or my call dropped.

EFR and AMR-Full rate codecs are VERY good, and effectively land line quality - without cutting background noise. I suspect that most (all) networks are set to AMR-half rate or anything even 'more' efficient (poorer quality). Skype actually has better audio at times.

Yep...I remember people asking me when I was on Sprint..."are you still there? It got quiet so I thought you got dropped".

I attached a screenshot of the only way I can get field test information (there has to be a better screen). I think I've always seen this "SpeechVER" listed as EFR FR not used. I assume this means I am on Enhanced Full Rate?
Attachment 83369

**zephxiii** · 07-27-2012, 05:48 AM

Remember that there isn't Full Rate or Half Rate on HSPA, it is just a bitrate which is typically set to 5.9 everywhere....which sounds quite good in my use.

**Shizam76** · 07-27-2012, 01:14 PM

Originally Posted by zephxiii

Remember that there isn't Full Rate or Half Rate on HSPA, it is just a bitrate which is typically set to 5.9 everywhere....which sounds quite good in my use.

Ahhhh....I didn't know that. See what happens when being gone for 2.5 yrs?? :-)

**zephxiii** · 07-27-2012, 01:29 PM

Originally Posted by Shizam76

Ahhhh....I didn't know that. See what happens when being gone for 2.5 yrs?? :-)

Yea, HR/FR was more about GSM and whether or not the phone was using every TDMA timeslot frame (Full rate) or every other frame (half rate).

**Shizam76** · 07-27-2012, 01:39 PM

When they eventually transition to VOLTE....will the quality of the audio get better?

**Nucleartx** · 07-27-2012, 03:57 PM

Originally Posted by zephxiii

Remember that there isn't Full Rate or Half Rate on HSPA, it is just a bitrate which is typically set to 5.9 everywhere....which sounds quite good in my use.

I saw AMR 12.5(or 12.2) on my SGS3 in Texas on my diagnostic mode before. Voice sounds pretty good around here most of the time.

**zephxiii** · 07-27-2012, 04:18 PM

Originally Posted by Nucleartx

I saw AMR 12.5(or 12.2) on my SGS3 in Texas on my diagnostic mode before. Voice sounds pretty good around here most of the time.

Awesome, i'll have to look at codecs again around here to see if it reads any different. Call quality has always been great here.

**dctmpeg** · 07-28-2012, 01:56 PM

It's often 5.9kbps but the minute data is pushed to and from the phone, while on a voice call, the network will often bump it up to 12.2kbps. In a similar sense, if the network wants 5.9k but the user is browsing the web, then makes call, if data is going back and fourth while the call is being setup, it's 12.2k.

5.9k to landline sounds pretty good. In particular, AT&T is using some type of brightness boost that makes the low bit-rate speech codecs sound better. T-Mobile has been doing something like this for years on their GSM network, which is why HR 6.70K often sound better than HR 7.40K on AT&T. Or, how, 4.75kbps [with almost no signal] sounds clearer than 5.9K on AT&T GSM...

12.2K to landline sounds even better. 5.9 to 5.9 sounds.... Well, usually quite awful. All one needs is an an older copy of Quicktime Pro (One of many possible AMR implementations on the Windows and Mac platform) and a linear PCM audio file as your source material (speech only) to demonstrate this effect... Lol.

Now the question becomes: How do these codecs compare in sound quality to the ULTRA low bit-rate speech codecs found on satellite phone networks? My understanding is that the proprietary and unknown AMBE codec at 2.0kbps is the norm...

**zephxiii** · 07-28-2012, 04:10 PM

Wat? AMR 5.9 to AMR 5.9 sounds great because it is the same codec, i use it all the time. It's when u call AMR to cdma is where both can sound really bad as they are different codecs that compress sound differently, typically when calling a verizon number.

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